Ring Oscillator Clock Startup Stabilization With Starting Voltage
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Solution Overview
Problem
Existing clock generating apparatuses face challenges in stabilizing the frequency of clock signals immediately after startup and in maintaining frequency stability under temperature variations, particularly in driving apparatuses that utilize ring oscillators.
Innovation Solution
A clock generating apparatus with a current-feedback-type configuration, incorporating a voltage control oscillator, control voltage generator, and starting voltage generator, which uses a bias current source, converters, and a starting circuit to stabilize the clock frequency by setting the control voltage to a starting voltage during the startup period, thereby stabilizing the frequency of the clock output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a ring oscillator is used to generate clock signals, then the circuit can be simple and compact, but the frequency stability immediately after startup deteriorates
Solution Approach 1:
The patent applies preliminary action by providing a starting voltage generator that generates a starting voltage before the main operation begins. This starting voltage is applied to the control electrode of the variable capacitor during the startup period, ensuring the ring oscillator reaches a stable operating state quickly. The control unit switches the capacitor connection based on the startup signal, implementing preliminary stabilization before normal frequency control begins.
2Measurement precision
If the control voltage is adjusted to correct frequency deviations, then the frequency accuracy improves, but frequency variations due to temperature changes worsen
Solution Approach 1:
The patent implements feedback by using a frequency detection circuit that continuously monitors the oscillation frequency and generates a control voltage based on detected frequency deviations. This control voltage is fed back to adjust the capacitance of the variable capacitor, automatically correcting frequency deviations. The feedback loop ensures frequency accuracy while compensating for temperature-induced variations through continuous adjustment.
3Reliability
If the startup period is extended to stabilize frequency, then frequency stability improves, but the time to reach operational state increases
Solution Approach 1:
The patent applies dynamics by making the capacitor connection state changeable based on the startup signal. During startup, the control unit connects the capacitor to a specific voltage level to stabilize frequency. Once the startup period ends and frequency is stable, the control unit switches the capacitor connection to normal operation mode. This dynamic switching optimizes both startup stabilization and operational performance without excessive delay.
Data Source
AI summary
Provided is a clock generating apparatus including a voltage control oscillator that outputs a clock corresponding to a control voltage which is input, a control voltage generator that generates the control voltage corresponding to a difference between a frequency of the clock and a target frequency, a starting voltage generator that generates a starting voltage which is supplied to the voltage control oscillator during a start period of the voltage control oscillator, and a starting circuit that sets the control voltage to the starting voltage during the start period after a start-up of the voltage control oscillator.